I would suggest you do an internet search on Discus care first...they have specialized needs regarding water parameters, water quality, tankmates, etc. Plan on about 10-15 gallons per adult discus. It use to be commonly thought that Angels carried diseases that affect discus. However with most angels being captive bred, more people are keeping angels with discus than before. They too can get relatively large and will need adequate space. I have kept clown loaches with discus in the past with no problems. Again, a large tank will be necessary. Some people prefer smaller, peaceful loaches with discus. Cardinal tetras, rams, cories are just some of the other species that also work well. I'm sure you will get a lot of other advise as well...some of it very contradictory. I don't think any other fish stirs up as much controversy and range of opinions. So take your time and take all the advise with a grain of salt. Do your homework, and look for the consistent information in the materials you review and in the advise you receive. Good luck and enjoy!